Fuel cell electric vehicle

ABSTRACT

A fuel cell electric vehicle includes a driving motor, a fuel cell and first and second supply/discharge manifolds. The driving motor is disposed between a pair of wheels. The fuel cell is disposed above the driving motor and has a plurality of unit cells stacked in a vertical direction of a vehicle. The fuel cell includes a plurality of through-manifolds configured and arranged to distribute a fuel gas, an oxidizing gas and a coolant to the unit cells. The first and second supply/discharge manifolds are disposed adjacent to first and second lateral end portions of the driving motor, respectively, with respect to a lateral direction of the vehicle. The first and second supply/discharge manifolds include a plurality of fluid connection ports for transporting the fuel gas, the oxidizing gas and the coolant at positions that substantially overlap with positions of the through-manifolds.

CROSS-REFERENCE TO RELATED APPLICATIONS

This U.S. National stage application claims priority to Japanese PatentApplication No. 2005-309865 filed on Oct. 25, 2005. The entiredisclosure of Japanese Patent Application No. 2005-309865 is herebyincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a mounting structure for mounting afuel cell on an electric vehicle. More specifically, the presentinvention relates to a fuel cell electric vehicle in which a fuel cellis mounted together with a driving motor.

2. Background Information

Japanese Laid-Open Patent Application No. 2003-173790 discloses aconventional fuel cell electric vehicle in which a fuel cell stack ismounted in a front compartment. The fuel cell stack is formed bystacking a plurality of unit fuel cells in the vertical direction withrespect to the vehicle.

In view of the above, it will be apparent to those skilled in the artfrom this disclosure that there exists a need for an improved fuel cellelectric vehicle. This invention addresses this need in the art as wellas other needs, which will become apparent to those skilled in the artfrom this disclosure.

SUMMARY OF THE INVENTION

In the conventional fuel cell electric vehicle described in the abovementioned reference, a large space is required for installing aplurality of fluid supply/discharge pipes for supplying and dischargingfuel cell fluids (such as fuel gas, oxidizing gas, etc.) used in thefuel cell stack in order to connect the fluid supply/discharge pipes toan upper side and a lower side of the fuel cell stack. Therefore, due tothis space requirement for the fluid supply/discharge pipes, the numberof the unit fuel cells stacked together to form the fuel cell stackcannot be greatly increased.

The present invention is contrived in light of the abovementionedproblem. Thus, it is an object of the present invention to provide afuel cell electric vehicle that can increase output power of the fuelcell by increasing the number of unit fuel cells stacked together toform a fuel cell stack.

In order to achieve the above mentioned object, a fuel cell electricvehicle is provided that basically comprises a driving motor, a fuelcell and first and second supply/discharge manifolds. The driving motoris disposed between a pair of wheels. The fuel cell is disposed abovethe driving motor having a plurality of unit cells stacked in a verticaldirection of a vehicle. The fuel cell includes a plurality ofthrough-manifolds configured and arranged to distribute a fuel gas, anoxidizing gas and a coolant to the unit cells. The first and secondsupply/discharge manifolds is disposed adjacent to first and secondlateral end portions of the driving motor, respectively, with respect toa lateral direction of the vehicle. The first and secondsupply/discharge manifolds are fluidly coupled to the through-manifoldsto transport the fuel gas, the oxidizing gas and the coolant relative tothe fuel cell. The supply/discharge manifolds includes a plurality offluid connection ports for transporting the fuel gas, the oxidizing gasand the coolant at positions that substantially overlap with positionsof the through-manifolds formed in the fuel cell in a top plan view ofthe vehicle.

These and other objects, features, aspects and advantages of the presentinvention will become apparent to those skilled in the art from thefollowing detailed description, which, taken in conjunction with theannexed drawings, discloses preferred embodiments of the presentinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the attached drawings which form a part of thisoriginal disclosure:

FIG. 1 is a left side schematic elevational view showing an arrangementof a power system of a fuel cell electric vehicle in accordance with afirst embodiment of the present invention;

FIG. 2 is a rear side perspective view of an area of the fuel cellelectric vehicle where a fuel cell is disposed illustrating a state inwhich a fuel cell housing is removed in accordance with the firstembodiment of the present invention;

FIG. 3 is a rear elevational view of the area of the fuel cell electricvehicle where the fuel cell is disposed illustrating a state in whichthe fuel cell housing is removed in accordance with the first embodimentof the present invention;

FIG. 4 is a top plan view of the area of the fuel cell electric vehiclewhere the fuel cell is disposed illustrating a state in which the fuelcell housing is removed in accordance with the first embodiment of thepresent invention;

FIG. 5 is an exploded front perspective view illustrating an attachmentstructure between the fuel cell and a pair of supply/discharge manifoldsin accordance with the first embodiment of the present invention;

FIG. 6 is a series of diagrams (a) to (g) illustrating a structure ofthe supply/discharge manifold in accordance with the first embodiment ofthe present invention, wherein the diagram (a) is a perspective view ofthe supply/discharge manifold as viewed from a first side thereof, thediagram (b) is a perspective view of the supply/discharge manifold asviewed from a second side thereof, the diagram (c) is a cross sectionalview of the supply/discharge manifold as taken along a section line 6c-6 c in the diagram (a), the diagram (d) is a cross sectional view ofthe supply/discharge manifold as taken along a section line 6 d-6 d inthe diagram (b), the diagram (e) is a cross sectional view of thesupply/discharge manifold as taken along a section line 6 e-6 e in thediagram (a), the diagram (f) is a cross sectional view of thesupply/discharge manifold as taken along a section line 6 f-6 f in thediagram (a), and the diagram (g) is a cross sectional view of thesupply/discharge manifold as taken along a section line 6 g-6 g in thediagram (a);

FIG. 7 is a rear side perspective view of the area of the fuel cellelectric vehicle where the fuel cell is disposed illustrating a state inwhich the fuel cell is housed inside the fuel cell housing that isfixedly coupled to a vehicle frame in accordance with the firstembodiment of the present invention;

FIG. 8 is rear side perspective view showing an attachment structure ofthe fuel cell and the supply/discharge manifolds to a vehicle frame inaccordance with a second embodiment of the present invention; and

FIG. 9 is a series of diagrams (a) to (e) illustrating a structure of asupply/discharge manifold in accordance with a third embodiment of thepresent invention, wherein the diagram (a) is a perspective view of thesupply/discharge manifold as viewed from a first side thereof, thediagram (b) is a perspective view of the supply/discharge manifold asviewed from a second side thereof, the diagram (c) is a cross sectionalview of the supply/discharge manifold as taken along a section line 9c-9 c in the diagram (a), the diagram (d) is a cross sectional view ofthe supply/discharge manifold as taken along a section line 9 d-9 d inthe diagram (b), and the diagram (e) is a cross sectional view of thesupply/discharge manifold as taken along a section line 9 e-9 e in thediagram (a).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Selected embodiments of the present invention will now be explained withreference to the drawings. It will be apparent to those skilled in theart from this disclosure that the following descriptions of theembodiments of the present invention are provided for illustration onlyand not for the purpose of limiting the invention as defined by theappended claims and their equivalents.

Referring initially to FIGS. 1 to 7, a fuel cell electric vehicle 1 isillustrated in accordance with a first embodiment of the presentinvention. FIG. 1 is a left side schematic elevational view showing anarrangement of a power system of the vehicle 1 in accordance with thefirst embodiment. As shown in FIG. 1, the vehicle 1 includes, amongother things, a passenger compartment 2, a motor room or motorcompartment 3, a trunk compartment 4, a pair of front wheels 5 (left andright front wheels) and a pair of rear wheels 6 (left and right rearwheels). The passenger compartment 2 is disposed in a generally centerpart of the vehicle 1 with respect to the longitudinal direction of thevehicle 1. The motor compartment 3 (also called an engine compartment, afront mechanical compartment, or a front box) is disposed in the frontpart of the vehicle 1. The trunk compartment 4 is disposed in the rearpart of the vehicle 1. As shown in FIG. 1, the front wheels 5 aredisposed under the motor compartment 3, and the rear wheels 6 aredisposed in the rear part of the passenger compartment 2. The arrow FRin FIG. 1 indicates the front direction, which is the direction oftravel of the vehicle 1.

As shown in FIG. 1, a fuel cell 10 is mounted inside the motorcompartment 3 above a driving motor 40, which is disposed between theleft and right front wheels 5. The fuel cell 10 is configured andarranged to generate electric power to drive the driving motor 40,thereby causing the front wheels 5 to rotate to move the vehicle 1. Thefuel cell 10 is housed inside a housing 300 (casing).

FIG. 2 is a rear side perspective view of an area inside the motorcompartment 3 where the fuel cell 10 is disposed. FIG. 3 is a rearelevational view of the area inside the motor compartment 3 where thefuel cell 10 is disposed. FIG. 4 is a top plan view of the area insidethe motor compartment 3 where the fuel cell 10 is disposed illustratinga state in which the fuel cell housing 300 is removed. FIGS. 2 to 4illustrates a state in which the fuel cell housing 300 is removed.

The fuel cell 10 is preferably a solid polymer electrolyte(polyelectrolyte) type fuel cell. As shown in FIG. 2, the fuel cell 10includes a pair of fuel cell stacks 10A and 10B, a lower end plate 11and an upper end plate 12. The fuel cell stacks 10A and 10B the lowerand upper end plates 11 and 12 are coupled together to form an integralfuel cell unit. As shown in FIG. 5, each of the fuel cell stacks 10A and10B is formed by stacking a plurality of unit cells 15 (unit fuelcells). Each of the unit cells 15 includes a membrane-electrode assemblyconstructed from an electrolyte membrane including an ion exchangemembrane, a fuel electrode disposed on one surface of the electrolytemembrane, and an air electrode disposed on the other surface of theelectrolyte membrane. A separator, which forms channels used to supplyfuel gas and oxidizing gas to the fuel electrode and the air electrode,respectively, is installed in the membrane-electrode assembly to formthe unit cell 15.

In the vehicle 1, as shown in FIG. 2, the two fuel cell stacks 10A and10B are aligned and combined in the longitudinal direction of thevehicle 1 to form the fuel cell 10 that has an integrated structure. Asmentioned above, the fuel cell 10 is positioned inside the motorcompartment 3 and mounted above the driving motor 40. In each of thefuel cell stacks 10A and 10B, the unit cells 15 are stacked in thevertical direction of the vehicle 1. In a top plan view, the unit cells15 in each of the fuel cell stacks 10A and 10B have an elongatedrectangular shape that is longer in the lateral direction of the vehicle1 and shorter in the longitudinal direction of the vehicle 1.Furthermore, the unit cells 15 having the rectangular shape are arrangedso that the fuel cell fluids (fuel gas, oxidizing gas, and coolant) flowin the unit cells 15 from one side of the vehicle 1 to the other sidewith respect to the lateral direction of the vehicle 1. As used herein,the “fuel cell fluids” includes the fuel gas, the oxidizing gas and thecoolant that are supplied to the fuel cell 10.

Furthermore, as seen in FIG. 3, the fuel cell 10 has a pair ofsupply/discharge manifolds 20 (first and second supply/dischargemanifolds). The supply/discharge manifolds 20 are installed as asupply/discharge manifold section on the left and right ends of thelower portions of the fuel cell stacks 10A and 10B (both lateral lowerend portions of the fuel cell stacks 10A and 10B with respect to thelateral direction of the vehicle 1) for distributing and collecting(converging) the fuel cell fluids (the fuel gas, the oxidizing gas, andthe coolant) with respect to the fuel cell stacks 10A and 10B. Morespecifically, the distribution of the fuel cell fluids into the fuelcell stacks 10A and 10B is carried out by one of the supply/dischargemanifolds 20 disposed on one side of the fuel cell 10, and thecollecting of the fuel cell fluids from the fuel cell stacks 10A and 10Bis carried out by the other one of the supply/discharge manifolds 20disposed on the other side of the fuel cell 10.

FIG. 5 is an exploded front perspective view of the fuel cell 10including the fuel cell stacks 10A and 10B and the supply/dischargemanifolds 20. As shown in FIG. 5, each of the fuel cell stacks 10A and10B includes a pair of through-manifolds 101, a pair ofthrough-manifolds 102 and a pair of through-manifolds 103 formed in bothlateral sides thereof, respectively. The through-manifolds 101, 102 and103 are configured and arranged to supply or discharge the fuel gas, theoxidizing gas, and the coolant to and from the unit cells 15 of each ofthe fuel cell stacks 10A and 10B. Generally, the through-manifolds 101,102 and 103 are formed by forming holes in each of the unit cells 15 atpositions corresponding to the through-manifolds 101, 102 and 103 fordistributing the fuel gas, the oxidizing gas, and the coolant to theinterior part of each of the unit cells 15, and then stacking the unitcells 15 so that these holes are aligned to fluidly communicate witheach other.

As seen in FIG. 5, as mentioned above, each of the fuel cell stacks 10Aand 10B includes the through-manifolds 101, 102 and 103 that are formedon both lateral ends of the corresponding one of the fuel cell stacks10A and 10B. More specifically, the through-manifolds 103 is used forthe coolant water, the through-manifolds 102 is used for the oxidizinggas, and the through-manifolds 101 is used for the fuel gas. Thethrough-manifolds 103, 102 and 101 are formed in that order from thefront in the fuel cell stack 10A disposed on the front side in thedirection of travel of the vehicle 1. Furthermore, the through-manifolds103, 102 and 101 are formed in that order from the rear in the fuel cellstack 10B disposed on the rear side in the direction of travel of thevehicle 1. In other words, in the fuel cell stack 10A on the front sideand the fuel cell stack 10B on the rear side, the order of arrangementof the through-manifolds 101, 102 and 103 are reversed, so that thethrough-manifolds 103 used for the coolant is positioned on theoutermost end (front or rear end) of the fuel cell 10, thethrough-manifolds 101 for the fuel gas is positioned on the innermostend, and the through-manifolds 102 for the oxidizing gas is positionedin an intermediate position between the through-manifolds 103 and thethrough-manifolds 101.

As mentioned above, each of the fuel cell stacks 10A and 10B has two ofthe through-manifolds 101 used for the fuel gas, two of thethrough-manifolds 102 used for the oxidizing gas, and two of thethrough-manifolds 103 used for the coolant that are disposed on the leftand right side of the respective fuel cell stack 10A or 10B,respectively. One of the through-manifolds 101, 102 and 103 is disposedon one side of the fuel cell stacks 10A and 10B to function as supplymanifolds and the other one of the through-manifolds 101, 102 and 103 isdisposed on the other side of the fuel cell stack 10A and 10B tofunction as discharge manifolds.

More specifically, the fuel gas is introduced to one of thesupply/discharge manifolds 20 attached to a first lateral end portion ofthe fuel cell 10 via a fuel gas pipe 21 (FIG. 2) coupled to thesupply/discharge manifold 20 attached to the first lateral end portionof the fuel cell 10. Then, the fuel gas is supplied and distributedinside the fuel cell stacks 10A and 10B (i.e., to each of the unit cells15 constituting the fuel cell stacks 10A and 10B) via thethrough-manifolds 101 formed in a first lateral side of the fuel cellstacks 10A and 10B. The fuel gas supplied to the fuel cell 10contributes to the power generating reaction in each of the unit cells15 of the fuel cell stacks 10A and 10B. Then, after the fuel gas is usedin the power generating reaction, the fuel gas flows into the other oneof the supply/discharge manifolds 20 attached to a second lateral endportion of the fuel cell 10 via the through-manifolds 101 formed in asecond lateral side of the fuel cell stacks 10A and 10B. Therefore, thefuel gas used in the fuel cell stacks 10A and 10B are collected togetherby the supply/discharge manifold 20 attached to the second lateral endportion of the fuel cell 10, and discharged to the outside via a fuelgas pipe 21 coupled to the supply/discharge manifold 20 attached to thesecond lateral end portion of the fuel cell 10.

Likewise, the oxidizing gas is introduced to one of the supply/dischargemanifolds 20 attached to a first lateral end portion of the fuel cell 10via an oxidizing gas pipe (not shown) coupled to the supply/dischargemanifold 20 attached to the first lateral end portion of the fuel cell10. Then, the oxidizing gas is supplied and distributed inside the fuelcell stacks 10A and 10B (i.e., to each of the unit cells 15 constitutingthe fuel cell stacks 10A and 10B) via the through-manifolds 102 formedin a first lateral side of the fuel cell stacks 10A and 10B. Theoxidizing gas supplied to the fuel cell 10 contributes to the powergenerating reaction in each of the unit cells 15 of the fuel cell stacks10A and 10B. Then, after the oxidizing gas is used in the powergenerating reaction, the oxidizing gas flows into the other one of thesupply/discharge manifolds 20 attached to a second lateral end portionof the fuel cell 10 via the through-manifolds 102 formed in a secondlateral side of the fuel cell stacks 10A and 10B. Therefore, theoxidizing gas used in the fuel cell stacks 10A and 10B are collectedtogether by the supply/discharge manifold 20 attached to the secondlateral end portion of the fuel cell 10, and discharged to the outsidevia a oxidizing gas pipe (not shown) coupled to the supply/dischargemanifold 20 attached to the second lateral end portion of the fuel cell10.

Likewise, the coolant is introduced to one of the supply/dischargemanifolds 20 attached to a first lateral end portion of the fuel cell 10via a coolant pipe coupled to the supply/discharge manifold 20 attachedto the first lateral end portion of the fuel cell 10. Then, the coolantis supplied and distributed inside the fuel cell stacks 10A and 10B(i.e., to each of the unit cells 15 constituting the fuel cell stacks10A and 10B) via the through-manifolds 103 formed in a first lateralside of the fuel cell stacks 10A and 10B. The coolant supplied to thefuel cell 10 contributes to adjust temperature of the fuel cell 10.Then, after adjusting the temperature of the fuel cell 10, the coolantflows into the other one of the supply/discharge manifolds 20 attachedto a second lateral end portion of the fuel cell 10 via thethrough-manifolds 103 formed in a second lateral side of the fuel cellstacks 10A and 10B. Therefore, the coolant used in the fuel cell stacks10A and 10B are collected together by the supply/discharge manifold 20attached to the second lateral end portion of the fuel cell 10, anddischarged to the outside via a coolant pipe coupled to thesupply/discharge manifold 20 attached to the second lateral end portionof the fuel cell 10.

With respect to the fuel cell stacks 10A and 10B that are aligned in thelongitudinal direction, each of the through-manifolds 101, 102 and 103of the fuel cell stack 10A and each of the through-manifolds 101, 102and 103 of the fuel cell stack 10B, which are disposed on the samelateral side of the fuel cell 10 and which are used for the same fuelcell fluid (the fuel gas, the oxidizing gas or the coolant) perform thesame function of supplying or discharging the fuel cell fluid. In otherwords, for example, in a case where the through-manifold 101 on the leftside of the fuel cell stack 10A is used for supplying the fuel gas tothe fuel cell stack 10A and the through-manifold 101 on the right sideis used for discharging the fuel gas from the fuel cell stack 10A, thethrough-manifold 101 formed on the left side of the fuel cell stack 10Bis similarly used for supplying the fuel gas to the fuel cell stack 10Band the through-manifold 101 on the right side of the fuel cell stack10B is used for discharging the fuel gas from the fuel cell stack 10B.The same is also true for the other through-manifolds 102 and 103 formedin the fuel cell stacks 10A and 10B.

However, the flow direction of each of the fuel cell fluids can bechanged among the different fuel cell fluids (the fuel gas, theoxidizing gas or the coolant). In other words, the arrangements of thesupply and discharge functions of the through-manifolds 101, 102 and 103(i.e., the flow direction of the fuel cell fluids in the fuel cellstacks 10A and 10B) can be determined independently of each other (thefuel gas, the oxidizing gas or the coolant). For example, thethrough-manifolds 102 that are disposed on the left side of the fuelcell stacks 10A and 10B can be used for discharging the oxidizing gasfrom the fuel cell stacks 10A and 10B, while the through-manifolds 101that are disposed on the same left side of the fuel cell stacks 10A and10B are used for supplying the fuel gas to the fuel cell stacks 10A and10B. In such case, the flow direction of the fuel gas inside the fuelcell stacks 10A and 10B is opposite from the flow direction of theoxidizing gas inside the fuel cell stacks 10A and 10B. It is preferableto arrange the through-manifolds 101 and 102 so that the flow directionof the fuel gas is opposite from the flow direction of the oxidizinggas.

As the fuel gas and the oxidizing gas are supplied to the unit cells 15of the fuel cell stacks 10A and 10B, a reaction in which hydrogen isconverted into hydrogen ions and electrons (H₂→2H⁺+2e⁻) occurs on thefuel electrode side in each of the unit cells 15, and a reaction inwhich water is produced by oxygen, the hydrogen ions that pass throughthe electrolyte membrane, and electrons that are supplied via anexternal circuit (2H⁺+2e⁻+(½)O₂→H₂O) occurs on the fuel electrode sideof each of the unit cells 15. The fuel cell 10 is formed by connectingin series a plurality (in this case, one pair) of such fuel cell stacks10A and 10B, and each of the fuel cell stacks 10A and 10B includes theunit cells 15, in which such reactions occur, stacked together.Therefore, the fuel cell 10 can generate several hundred volts ofelectric power.

Next, referring back to FIGS. 1 and 2, the power system of the vehicle 1using the fuel cell 10 as a power source will be described.

As shown in FIGS. 1 and 2, the power system of the vehicle 1 preferablyincludes a power plant (not indicated by any particular referencenumeral) having the fuel cell 10 and auxiliary devices, a fuel gasstorage tank 65, a power control device (not shown), the front wheeldriving motor 40 and/or a rear wheel driving motor (not shown), a systemcontroller (not shown), an electric power storage device (not shown) anda low-voltage and a high-voltage electrical cables. As mentioned above,the fuel cell 10 is configured and arranged to generate electric powerby a reaction between the fuel gas and the oxidizing gas. The auxiliarydevices of the power plant are actuated during the generation of powerby the fuel cell 10. The fuel gas storage tank 65 stores the fuel gas.The power control device is configured to control the power generated bythe fuel cell 10, and to adjust the supply of power to the respectiveparts of the vehicle 1. The driving motor 40 is coupled to the frontwheels 5, and is configured and arranged to drive the front wheels 5using the power generated by the fuel cell 10 and adjusted by the powercontrol device. The system controller is configured to monitor theoperating conditions of the vehicle 1 and the fuel cell 10, and to sendcontrol signals to the auxiliary devices and other devices. The electricpower storage device is configured and arranged to accumulate or storethe electric power if necessary. The low-voltage and high-voltage linesare used for the operation of the various types of auxiliary devices ofthe vehicle 1. Furthermore, a high-power system component 60 (powercontrol device) is mounted under the floor of the passenger compartment2 of the vehicle 1 as shown in FIG. 1.

In this embodiment of the present invention, the abovementionedauxiliary devices of the power plant preferably include a fuel gassupply device 31 (hydrogen system part), an oxidizing gas supply device32 (air system part), a temperature adjustment device (a radiator 50,etc.), and the like as shown in FIG. 1.

The fuel gas supply device 31 is configured and arranged to adjust thepressure, temperature, flow rate, and the like of the fuel gas (mainlyhydrogen, but may also be a modified gas such as methanol or the like,or some other modified gas), and to supply the fuel gas to the fuel cell10. For example, the fuel gas supply device 31 includes a mass flowmeter configured and arranged to adjust the pressure, temperature, andflow rate of the fuel gas, and/or a fuel gas supply pump.

The oxidizing gas supply device 32 is configured and arranged to adjustthe pressure, temperature, flow rate, and the like of the oxidizing gas(mainly air), and to supply the oxidizing gas to the fuel cell 10. Forexample, the oxidizing gas supply device 32 includes a mass flow meterwhich is configured and arranged to adjust the pressure and flow rate ofthe oxidizing gas, a dust collector which is configured and arranged toremove foreign matter from the oxidizing gas, an air compressorconfigured and arranged to pressurize the oxidizing gas, a humidifierconfigured and arranged to adjust the humidity of the oxidizing gas,and/or a diluter configured and arranged to dilute the oxidizing gasafter the gas has passed through the fuel cell.

The temperature adjustment device (such as the radiator 50) isconfigured and arranged to adjust the temperature of the fuel cell 10 toan appropriate operating temperature. For example, the temperatureadjustment device includes a coolant circulating pump configured andarranged to supply the coolant to the fuel cell 10, a heat exchangecycle device configured and arranged to dissipate the heat generated bythe fuel cell 10 via a heat exchanger (e.g., the coolant), a heaterconfigured and arranged to heat the fuel cell 10 by electricallygenerated heat or combustion heat when the temperature of the fuel cell10 is low, and the like. In this illustrated embodiment, the radiator 50is provided as the temperature adjustment device.

During the operation of the vehicle 1, the reaction gases (the fuel gasand the oxidizing gas) are supplied to the fuel cell 10 from the fuelgas supply device 31 and oxidizing gas supply device 32, respectively,based on an opening degree of an accelerator of the vehicle 1. The power(electricity) generated in the fuel cell 10 is transmitted through apower blocking device (not shown), and is adjusted to the power requiredfor the respective parts of the vehicle 1 by the power control device.The power is then supplied to the front wheel driving motor 40. Thetorque of the driving motor 40 is transmitted to a drive shaft 41 torotate the drive wheels 5 of the vehicle 1.

As mentioned above, the system controller (not shown) is configured tomonitor the operating conditions of the vehicle 1 and the operatingconditions of the fuel cell 10, and to send control signals to theauxiliary devices and other devices of the vehicle 1. Therefore, thesystem controller is configured to control the respective devices of thevehicle 1 to the appropriate operating conditions.

In the first embodiment of the present invention, as shown in FIGS. 1and 7, the two fuel cell stacks 10A and 10B in which a plurality of theunit cells 15 are stacked in the vertical direction of the vehicle 1 areaccommodated in the housing 300. The supply/discharge manifolds 20 aredisposed on the left and right ends of the lowermost surface in thestacking direction (vertical direction of the vehicle 1) of the fuelcell 10 housed inside the housing 300. As shown in FIG. 3, thesupply/discharge manifolds 20 are respectively disposed on the left andright side of the upper portion of the driving motor 40. Morespecifically, the supply/discharge manifolds 20 are respectivelyinstalled in a pair of open spaces formed above the left and right endportions of the drive shaft 41 coupled to the driving motor 40.

Since the open spaces formed above the left and right end portions ofthe drive shaft 41 are extremely small, these open spaces are unsuitablefor mounting the auxiliary devices of the fuel cell system that requiresa large space. However, these open spaces are optimal for installing thesupply/discharge manifolds 20, which are relatively small components. Byinstalling the supply/discharge manifolds 20 in these open spaces, it ispossible to set the vertical positions of lower ends of thesupply/discharge manifolds 20 below the upper end of the driving motor40 as shown in FIG. 3.

In cases where the fluid supply/discharge parts are disposed entirely onthe undersurfaces of the fuel cell stacks as in the conventional fuelcell electric vehicle, the fluid supply/discharge parts must beinstalled in positions above the upper end of the driving motor.Therefore, the size of the fuel cell positioned above the fluidsupply/discharge parts cannot be increased, which makes it impossible toincrease the number of stacked unit cells in the fuel cell stacks in theconventional fuel cell electric vehicle. On the other hand, in the firstembodiment of the present invention, the number of the unit cells 15stacked together to form each of the fuel cell stacks 10A and 10B can befreely increased regardless of the height of the supply/dischargemanifolds 20 by disposing the supply/discharge manifolds 20 in the openspaces formed above the left and right end portions of the drive shaft41. Accordingly, the output of the fuel cell 10 can be increased byincreasing the number of the unit cells 15 stacked together to form eachof the fuel cell stacks 10A and 10B.

For example, when the thickness (height) of each of the fluidsupply/discharge manifolds 20 is set at several tens of millimeters andwhen the fluid supply/discharge part of the conventional fuel cellelectric vehicle 1 is, for example, 50 millimeters, the number of theunit cells 15 stacked together to form the fuel cell stacks 10A and 10Bcan be increased by the height of the fluid supply/discharge part of theconventional fuel cell electric vehicle 1. In other words, when thethickness of each of the unit cells 15 is 2 millimeters, the number ofthe unit cells 15 can be increased by a maximum of 25 unit cells. Insuch case, output of the fuel cell 10 can be increased by approximately10%.

As shown in FIG. 3, since the supply/discharge manifolds 20 are disposedadjacent to both lateral end portions (left and right end portions) ofthe upper part of the driving motor 40, the length of the oblong shape(extending in the lateral direction of the vehicle 1) of the unit cells15 in the fuel cell stacks 10A and 10B can be extended so that the unitcells 15 reach structural members of the vehicle 1 such as a pair ofside frame members 7 of the vehicle frame. Accordingly, the area of eachof the unit cells 15 in which the fuel gas and the oxidizing gas reactcan also be sufficiently increased, so that the current generated byeach of the unit cells 15 can be increased as well.

Since the supply/discharge manifolds 20 are disposed on the lowermostportions of the fuel cell stacks 10A and 10B, the water produced by thechemical reaction of the fuel cell 10 can be quickly discharged to thesupply/discharge manifolds 20 from the fuel cell stacks 10A and 10B bythe force of gravity. Therefore, the fuel cell 10 is less likely to haveinadequate power generating performance due to flooding (a phenomenon inwhich the gas diffusion layer is prevented from functioning by water,and thus, the chemical reaction tends not to proceed or is disrupted)and the like.

Since the supply/discharge manifolds 20 are disposed adjacent to bothlateral end portions (left and right end portions) of the upper part ofthe driving motor 40, the height of the supply/discharge manifolds 20can be increased without interfering with the large-diameter portion ofthe driving motor 40. Therefore, more water produced by the chemicalreaction can be accumulated inside the supply/discharge manifolds 20,the water produced by the fuel cell stacks 10A and 10B can be dischargedmore easily, and the fuel cell 10 is less likely to have inadequatepower generating performance due to flooding (a phenomenon in which thegas diffusion layer is prevented from functioning by water, and thus,the chemical reaction tends not to proceed or is disrupted) and thelike.

Furthermore, in this embodiment of the present invention, the area inwhich the supply/discharge manifolds 20 and the fuel cell stacks 10A and10B are sealed (i.e., the area in which the supply/discharge manifolds20 and the fuel cell stacks 10A and 10B contact each other via gaskets)can also be made extremely small. Therefore, the sealing properties ofthe overall connection surfaces between the supply/discharge manifolds20 and the fuel cell stacks 10A and 10B can be improved.

The supply/discharge manifolds 20 of the first embodiment are madecompact because the supply/discharged manifolds 20 are spaced apart inthe lateral direction of the vehicle 1. Therefore, the performance ofthe auxiliary devices of the fuel cell 10 can be improved by reducingthe size and weight of the fuel cell system as a whole and by furtherexpanding the spaces for other parts of the vehicle 1.

Next, the structure of the supply/discharge manifolds 20 and the fuelcell stacks 10A and 10B will be described in further detail withreference to FIGS. 5 and 6.

As mentioned above, the fuel cell 10 includes the two fuel cell stacks10A and 10B formed by stacking the unit cells 15, a lower endplate 11and an upper endplate 12 as shown in FIG. 5. The lower endplate 11 isinstalled in common on lower surfaces of the fuel cell stacks 10A and10B, and the upper endplate 12 is installed in common on upper surfacesof the fuel cell stacks 10A and 10B. Although not shown in FIG. 5, thehousing 300 (FIGS. 1 and 7) is provided to house the fuel cell 10, thelower endplate and the upper endplate 12 therein. The two fuel cellstacks 10A and 10B are aligned in the longitudinal direction of thevehicle 1 and mounted on the vehicle 1. As described above, thethrough-manifolds 101 for the fuel gas, the through-manifolds 102 forthe oxidizing gas, and the through-manifolds 103 for the coolant areformed by holes or openings formed in each of the unit cells 15 thatcollectively form the fuel cell stacks 10A and 10B.

As shown in FIG. 5, the lower endplate 11 also includes a plurality ofthrough-holes 111, 112 and 113 formed in positions that overlap with thethrough-manifolds 101, 102 and 103, respectively, of the fuel cellstacks 10A and 10B in a top plan view. Therefore, the through-holes 111,112 and 113 of the lower endplate 11 fluidly communicate with thethrough-manifolds 101, 102 and 103, respectively, of the fuel cellstacks 10A and 10B.

As described above, the supply/discharge manifolds 20, each of which hasa solid-rectangular block-shape, are disposed on the lower parts of theleft and right end portions of the fuel cell 10 in the lateral directionof the vehicle 1. The supply/discharge manifolds 20 are coupled to theundersurface of the fuel cell 10 (undersurface of the lower endplate 11)via a pair of gaskets 13 as shown in FIG. 5.

Each of the supply/discharge manifolds 20 includes a fluid connectionport 201, a pair of fluid connection ports 202 and a pair of fluidconnection ports 203. The fluid connection port 201 is formed in aposition that corresponds to the through-manifolds 101 so that the fluidconnection port 201 of the supply/discharge manifold 20 and thethrough-manifolds 101 are fluidly communicated with each other when thesupply/discharge manifold 20 is coupled to the fuel cell 10 (via thelower endplate 11 and the gasket 13). The fluid connection ports 202 areformed in positions that correspond to the through-manifolds 102 so thatthe fluid connection ports 202 of the supply/discharge manifold 20 andthe through-manifolds 102 are fluidly communicated with each other whenthe supply/discharge manifold 20 is coupled to the fuel cell 10 (via thelower endplate 11 and the gasket 13). Likewise, the fluid connectionports 203 are formed in positions that correspond to thethrough-manifolds 103 so that the fluid connection ports 203 of thesupply/discharge manifold 20 and the through-manifolds 103 are fluidlycommunicated with each other when the supply/discharge manifold 20 iscoupled to the fuel cell 10 (via the lower endplate 11 and the gasket13). Each of the gaskets 13 includes a through-hole 131, a pair ofthrough-holes 132 and a pair of through-holes 133 in positionscorresponding to the fluid connection ports 201, 202 and 203,respectively, formed on the upper end surface of the supply/dischargemanifold 20.

The fluid connection port 201 of each of the supply/discharge manifolds20 is disposed in an innermost (central) position among the fluidconnection ports 201, 202 and 203. The fluid connection port 201 of eachof the supply/discharge manifolds 20 is a fluid port used for the fuelgas, and formed as an elongated slot so that the fluid connection port201 is fluidly communicated with both of the through-manifolds 101 usedfor the fuel gas formed on one lateral side of the fuel cell stacks 10Aand 10B. Furthermore, the two adjacent fluid connection ports 202 ofeach of the supply/discharge manifolds 20 are fluid ports used for theoxidizing gas, and are formed so as to communicate with thethrough-manifolds 102 used for the oxidizing gas formed on one lateralside of the fuel cell stacks 10A and 10B, respectively. Furthermore, thefluid connection ports 203 positioned adjacent to the fluid connectionports 202 (disposed on the outermost side, i.e., both longitudinal endsof the supply/discharge manifolds 20 with respect to the vehicle 1) arefluid ports used for the coolant water, and are formed so as tocommunicate with the through-manifolds 103 used for the coolant waterformed on one lateral side of the fuel cell stacks 10A and 10B,respectively.

In the first embodiment of the present invention, the fluid connectionports 201, 202 and 203 of each of the supply/discharge manifolds 20 thatcause the fuel cell fluids to flow through the fuel cell stacks 10A and10B from the supply/discharge manifolds 20, and the through-manifolds101, 102 and 103 formed through the fuel cell stacks 10A and 10B inorder to supply and discharge the fuel cell fluids to and from each ofthe unit cells 15, are disposed in positions so that the fluidconnection ports 201, 202 and 203 overlap with the through-manifolds101, 102 and 103 in a top plan view. As a result, a region in which thesupply/discharge manifolds 20 and the fuel cell stacks 10A and 10B arecoupled together can be reduced to allow reliable sealing of thethrough-manifolds 101, 102 and 103. In other words, the sealing regionbetween the supply/discharge manifolds 20 and the fuel cell 10 can beminimized. As a result, the probability of fuel gas leakage due todefective sealing or the like can be reduced compared to cases where theentire surfaces of the fuel cell stacks are sealed as in theconventional fuel cell electric vehicle.

As shown in FIG. 6, the fluid connection port 201 of each of thesupply/discharge manifolds 20 used for the fuel gas fluidly communicateswith a connection port 221 that is formed on a surface (e.g., a firstside surface) of the supply/discharge manifold 20 other than the uppersurface thereof via an internal channel 211 (fluid channel). The fluidconnection ports 202 of each of the supply/discharge manifolds 20 usedfor the oxidizing gas fluidly communicate with a connection port 222that is formed on a surface (e.g., a second side surface) of thesupply/discharge manifold 20 other than the upper surface thereof via aninternal channel 212 (fluid channel). The fluid connection ports 203 ofeach of the supply/discharge manifolds 20 used for the coolant fluidlycommunicate with a connection port 223 that is formed on a surface(e.g., a third bottom surface) of the supply/discharge manifold 20 otherthan the upper surface thereof via an internal channel 213 (fluidchannel). The connection ports 221, 222 and 223 are preferably formed inoutside surfaces (the first, second and third surfaces) of thesupply/discharge manifold 20 other than the upper end surface thereof.

The fluid communication relationships are indicated by the arrows A, Band C in FIG. 6. On one lateral side of the fuel cell 10, the fuel gas Aenters into the supply/discharge manifold 20 via the connection port221, and leaves from the fluid connection port 201 via the internalchannel 211 into the fuel cell stacks 10A and 10B. On the other lateralside of the fuel cell 10, the discharged fuel gas from the fuel cellstacks 10A and 10B enters into the supply/discharge manifold 20 via thefluid connection port 201, and leaves from the connection port 221 viathe internal channel 211. On one lateral side of the fuel cell 10, theoxidizing gas B enters into the supply/discharge manifold 20 via theconnection port 222, and leaves from the fluid connection ports 202 viathe internal channel 212 into the fuel cell stacks 10A and 10B. On theother lateral side of the fuel cell 10, the discharged oxidizing gasfrom the fuel cell stacks 10A and 10B enters into the supply/dischargemanifold 20 via the fluid connection ports 202, and leaves from theconnection port 222 via the internal channel 212. On one lateral side ofthe fuel cell 10, the coolant C enters into the supply/dischargemanifold 20 via the connection port 223, and leaves from the fluidconnection ports 203 via the internal channel 213 into the fuel cellstacks 10A and 10B. On the other lateral side of the fuel cell 10, thedischarged coolant from the fuel cell stacks 10A and 10B enters into thesupply/discharge manifold 20 via the fluid connection ports 203, andleaves from the connection port 223 via the internal channel 213.

The connection port 221 of each of the supply/discharge manifolds 20used for the fuel gas is formed in the inside surface of thesupply/discharge manifolds 20 so that the connection ports 221 for thefuel gas are disposed inside surfaces of the supply/discharge manifolds20 disposed on the left or right end portions of the fuel cell 10. Asshown in FIG. 2, the fuel gas pipes 21 are connected, from the inside inthe lateral direction of the vehicle 1, to the connection ports 221(connected to the fuel gas channel 211), respectively, of thesupply/discharge manifolds 20. One of the fuel gas pipes 21 is used forsupplying the fuel gas to the fuel cell 10, and the other one of thefuel gas pipes 21 is used for discharging the fuel gas from the fuelcell 10. At least one of the fuel gas pipes 21 that is used forsupplying the fuel gas to the fuel cell 10 is connected via the fuel gassupply device 31 to the fuel gas storage tank 65 mounted in the vehicle1.

Each of the connection ports 222 used for the oxidizing gas is formed inthe outside surface of the corresponding one of the respectivesupply/discharge manifolds 20 with respect to the lateral direction ofthe vehicle 1, and a pair of oxidizing gas pipes (not shown) isconnected, from the outside in the lateral direction of the vehicle 1,to the oxidizing gas connection ports 222 (connected to the oxidizinggas channel 212) in the supply/discharge manifolds 20, respectively. Inthis case as well, one of the oxidizing gas pipes is used for supplyingthe oxidizing gas to the fuel cell 10, and the other one of theoxidizing gas pipes is used for discharging the oxidizing gas from thefuel cell 10. At least one of the oxidizing gas pipes that is used forsupplying the oxidizing gas to the fuel cell 10 is connected to theoxidizing gas supply device 32.

Each of the connection ports 223 used for the coolant is formed in theundersurface (bottom surface) of the corresponding one of thesupply/discharge manifolds 20 disposed on the left and right of the fuelcell 10. The connection ports 223 may be formed on the front surface(facing in the direction of travel of the vehicle 1) of thesupply/discharge manifold 20 instead of the bottom surface thereof. Apair of coolant pipes 55 (one coolant pipe 55 shown in FIG. 2) isconnected to the coolant water connection ports 223 of thesupply/discharge manifolds 20, respectively. In this case as well, oneof the coolant pipes 55 is used for supplying the coolant to the fuelcell 10 and the other one of the coolant pipes 55 is sued fordischarging the coolant from the fuel cell 10. The coolant pipes 55 arepreferably connected to the radiator 50 that serves as the heatingcontrol device.

As a result of these piping connections, the fuel gas, the oxidizinggas, and the coolant are distributed to the fuel cell stacks 10A and 10Bfrom the supply/discharge manifold 20 disposed on one of the left andright ends of the lower parts of the fuel cell stacks 10A and 10Bthrough the through-manifolds 101, 102 and 103 of the fuel cell stacks10A and 10B. Then, the fuel gas, the oxidizing gas, and the coolant aredistributed to the respective unit cells 15 of the fuel cell stacks 10Aand 10B, so that electrical power is generated by a reaction at thesurfaces of the unit cells 15. Then, after the generation of electricalpower in the fuel cell stacks 10A and 10B, the fuel gas, the oxidizinggas, and the coolant are collected and flow into the supply/dischargemanifold 20 on the opposite side, and the fuel cell fluids are collectedby the corresponding one of the pipes coupled to the supply/dischargemanifold 20.

The left and right supply/discharge manifolds 20 have an identicalshape. Therefore, the number of parts required is reduced and theassembly characteristics of the fuel cell system can be improved (e.g.,the assembly time can be shortened).

It is preferable to directly couple the housing 300 of the fuel cell 10with the supply/discharge manifolds 20 by bolts or the like with thegaskets 13 sandwiched therebetween without any other elastic membersbeing interposed. The direction of attachment (e.g., direction of thebolt insertion) in this case may be from the side of thesupply/discharge manifolds 20 or from the side of the housing 300 of thefuel cell 10. By directly connecting the fuel cell 10 and thesupply/discharge manifolds 20, the amount of piping, hosing, or the likeused to connect the fuel cell 10 and the supply/discharge manifolds 20can be reduced. Accordingly, the number of parts required can be reducedand weight of the fuel cell system may be reduced too. Furthermore, evenin cases where a physical object enters into the motor compartment 3from the outside due to a vehicle collision or the like, the possibilityof damaging the piping, hoses, or the like can be reduced.

Since the housing 300 of the fuel cell 10 and the supply/dischargemanifolds 20 effectively formed as an integral rigid body, possibilityof shifting of the sealing parts between the supply/discharge manifolds20 and the fuel cell 10 can be reduced in the case of a vehiclecollision or the like.

FIG. 7 is a rear side perspective view of the area inside the motorcompartment 3 where the fuel cell 10 is disposed illustrating a state inwhich the fuel cell housing 300 is coupled to the fuel cell 10 andillustrating an attachment structure between the housing 300 and theside frame members 7 of the vehicle 1 in accordance with the firstembodiment. In the example shown in FIG. 7, a single rigid body in whichthe supply/discharge manifolds 20 are directly connected to the housing300 of the fuel cell 10 is fastened to the side frame members 7 of thevehicle frame via a pair of mounting brackets 71. The mounting brackets71 are preferably attached in advance to the housing 300 of the fuelcell 10, and each of the mounting brackets 71 is tightened on thecorresponding one of the side frame members 7 by a pair of bolts 72.Therefore, the fuel cell 10 and the housing 300 are supported by thevehicle body frame. In this case, since the dimension of the fuel cell10 in the longitudinal direction (dimension in the lateral direction ofthe vehicle 1) can be extended to the vicinity of the side frame members7 because of the relationship in which the supply/discharge manifolds 20are disposed on both lateral ends of the upper portion of the drivingmotor 40, there is no loss of space for installing peripheral parts byattaching the fuel cell 10 to the side frame members 7.

Since the housing 300 of the fuel cell 10 extends as a bridge betweenthe left and right side frame members 7, the housing 300 of the fuelcell 10 plays a role equivalent to that of a cross member of the vehiclebody frame. Accordingly, especially in the case of a vehicle sidecollision, it is possible to securely prevent damage to the fuel cell 10or the supply/discharge manifolds 20 due to the entry of the side framemembers 7 or external physical objects into the motor compartment 3.

In the present invention, the fuel gas supply components other than thefuel gas pipes 21 and the fuel gas storage tank 65 may be disposed inany position inside the motor compartment 3. However, considering theconnection characteristics of the rear fuel gas storage tank 65 and thefuel gas pipes 21, it is desirable that the fuel gas supply componentsbe disposed rearwardly of the fuel cell 10 or under the floor panel ofthe passenger compartment 2.

Accordingly, in the present invention, the fluid supply/dischargemanifolds 20 are disposed on the left and right end portions of thelowermost part of the fuel cell 10 and the left and right end portionsof the upper side of the driving motor 40. In other words, thesupply/discharge manifolds 20 are spaced apart on the left and rightside of the fuel cell 10 and disposed in the open spaces formed in theleft and right end portions of the upper side of the driving motor 40.Since the driving motor 40 has a larger diameter portion in the centerin the axial direction (the lateral direction of the vehicle 1), and adiameter of the driving motor 40 decreases toward the lateral endportions, the open spaces are formed on the upper side of the left andright end portions of the drive shaft 41. Accordingly, at least part ofthe undersurface of the fuel cell 10 can be utilized as a stacking spacefor the unit cells 15, thereby making it possible to increase the numberof unit cells 15 that are stacked to form the fuel cell stacks 10A and10B. Therefore, the output of the fuel cell 10 can be increased byincreasing the number of stacked unit cells 15.

Second Embodiment

Referring now to FIG. 8, a fuel cell electric vehicle in accordance witha second embodiment will now be explained. In view of the similaritybetween the first and second embodiments, the parts of the secondembodiment that are identical to the parts of the first embodiment willbe given the same reference numerals as the parts of the firstembodiment. Moreover, the descriptions of the parts of the secondembodiment that are identical to the parts of the first embodiment maybe omitted for the sake of brevity.

FIG. 8 is rear side perspective view showing an attachment structure ofthe fuel cell 10 housed inside the housing 300 and the supply/dischargemanifolds 20 to the side frame members 7 in accordance with a secondembodiment of the present invention. In the second embodiment, thesupply/discharge manifolds 20 that are directly connected to the housing300 of the fuel cell 10 are fastened to the side frame members 7 of thevehicle frame via a pair of mounting brackets 75. In this respect, thesecond embodiment differs from the first embodiment, in which thehousing 300 of the fuel cell 10 is directly fastened to the side framemembers 7 as shown in FIG. 7. The fuel cell 10 can be supported byfastening the supply/discharge manifolds 20 to the side frame members 7.Although, in the illustrated embodiment, the supply/discharge manifolds20 are fastened to the side frame members 7 via the mounting brackets75, it would also be possible to fasten the supply/discharge manifolds20 directly to the side frame members 7 without interposing suchmounting brackets 75. Except for the attachment structure between thefuel cell 10 and the side frame members 7, the second embodiment hasexactly the same construction as the first embodiment. Accordingly, thesame effects as those of the first embodiment can be obtained in thesecond embodiment of the present invention.

Third Embodiment

Referring now to FIG. 9, a fuel cell electric vehicle in accordance witha third embodiment will now be explained. In view of the similaritybetween the first and third embodiments, the parts of the thirdembodiment that are identical to the parts of the first embodiment willbe given the same reference numerals as the parts of the firstembodiment. Moreover, the descriptions of the parts of the thirdembodiment that are identical to the parts of the first embodiment maybe omitted for the sake of brevity. The parts of the third embodimentthat differ from the parts of the first embodiment will be indicatedwith a single prime (′).

FIG. 9 is a series of diagrams (a) to (e) illustrating a structure of asupply/discharge manifold 20′ in accordance with a third embodiment ofthe present invention, wherein the diagram (a) is a perspective view ofthe supply/discharge manifold 20′ as viewed from a first side thereof,the diagram (b) is a perspective view of the supply/discharge manifold20′ as viewed from a second side thereof, the diagram (c) is a crosssectional view of the supply/discharge manifold 20′ as taken along asection line 9 c-9 c in the diagram (a), the diagram (d) is a crosssectional view of the supply/discharge manifold 20′ as taken along asection line 9 d-9 d in the diagram (b), and the diagram (e) is a crosssectional view of the supply/discharge manifold 20′ as taken along asection line 9 e-9 e in the diagram (a).

The third embodiment of the present invention is identical to the firstembodiment except that the supply/discharge manifolds 20′ are used inthe third embodiment instead of the supply/discharge manifolds 20. Morespecifically, each of the supply/discharge manifolds 20′ of the thirdembodiment is constructed as a split structure formed by combining twomembers. In other words, two members are coupled together at a jointsurface 250 as shown in the diagrams (a) and (b) of FIG. 9 to form thesupply/discharge manifold 20′. When the supply/discharge manifolds 20′is constructed by coupling two members as in the third embodiment,right-angle bending of internal channels 212′ and 213′ can be abolished,unlike in the first embodiment shown in FIG. 6. Accordingly, in caseswhere the fuel cell fluids (the fuel gas, the oxidizing gas and thecoolant) are supplied to the fuel cell stacks 10A and 10B, the pressureloss of the fuel cell fluids can be reduced. Therefore, the powergeneration performance of the fuel cell 10 may be improved.

Although in FIGS. 6 and 9, the supply/discharge manifolds 20 and 20′ areillustrated as being made of metal material, it is preferable from thestandpoint of securing strength of the supply/discharge manifolds 20 or20′ to use resins, especially reinforced plastics, as the material forthe supply/discharge manifolds 20 or 20′ than to use metals. On theother hand, in cases where a metal material is used for thesupply/discharge manifolds 20 or 20′, it is preferable to apply anon-conductive material coating on the coolant channel (the internalchannels 213 and 213′), where it is desired to maintain the insulationresistance. In case where the supply/discharge manifolds 20 or 20′ aremade of metal material, it is easy to maintain the strength when thesupply/discharge manifolds 20 or 20′ are fastened to the vehicle bodyside frame members 7, as in the example shown in FIG. 8.

In the first through third embodiments described above, the fluidconnection ports 201, 202 and 203 of the supply/discharge manifolds 20are arranged in positions that overlap with the through-manifolds 101,102 and 103, respectively, formed in the fuel cell stacks 10A and 10B ina top plan view. Therefore, the cross-sectional area of each of thefluid supply/discharge manifolds 20 can be reduced to a range thatallows sealing of the through-manifolds 101, 102 and 103 of the unitcells 15. Accordingly, the sealing range of the supply/dischargemanifolds 20 and the fuel cell 10 can be minimized, and thus, defectivesealing can be reduced. Moreover, since the size of the supply/dischargemanifolds 20 can be minimized, the size and weight of the fuel cellsystem as a whole can be further reduced. In addition, the fuel cellfluids discharged from the fuel cell stacks 10A and 10B can be conveyedto the supply/discharge manifolds 20 over a minimal distance. Therefore,the water produced inside the fuel cell stacks 10A and 10B can bequickly discharged into the supply/discharge manifolds 20 by the forceof gravity, so that defective power generation caused by flooding can beprevented.

In the first through third embodiments described above, the coolantchannel 213 (connected to the coolant connection ports 203) are disposedin the outer most positions than the fuel gas channel 211 (connected tothe fuel gas connection ports 201), the oxidizing gas channel 212(connected to the oxidizing gas connection ports 202). Therefore,insulation of the fuel cell 10 from the outside parts is possible bymaintaining a sufficient insulation distance inside the supply/dischargemanifolds 20 even in cases where the coolant circulates through the fuelcell stacks 10A and 10B that generate a high voltage of several hundredvolts.

Specifically, since the fuel cell 10 generates a high voltage, it isnecessary to prevent the transmission of a high voltage via the coolantin cases where the coolant passing through the internal partsdeteriorates. Accordingly, in the first through third embodimentsdescribed above, the fluid channel 213 (connected to the fluidconnection ports 203) through which the coolant from the outlet side ofthe fuel cell stacks 10A and 10B flows are disposed on the outermostsides in the supply/discharge manifolds 20. As a result, the insulationresistance can be maintained inside the supply/discharge manifolds 20.

Moreover, the distance between the radiator 50 disposed on the front endof the vehicle 1 and the coolant channel 213 (connected to the coolantconnection ports 203) can also be shortened so that a reduction inweight can be achieved by shortening the coolant pipes 55 or hoses fromthe radiator 50 to the coolant ports 203 of the supply/dischargemanifolds 20. In other words, as shown in FIG. 2, it is necessary toremove the heat absorbed inside the fuel cell 10 while the coolant,which has passed through the fuel cell 10, passes through the radiator50 at the front of the vehicle 1. In this case, the piping and hosesdisposed between the radiator 50 and the supply/discharge manifolds 20)can be improved by placing the coolant channel 213 (connected to thefluid connection ports 203) on the outermost side of thesupply/discharge manifolds 20, and the distance of the coolant pipe 55and hoses that connect the radiator 50 and the coolant channel 213(connected to the fluid connection ports 203) of the supply/dischargemanifolds 20 can be minimized. Accordingly, the weight of the vehicle 1may be reduced and the productivity of the fuel cell system may beimproved.

In the present invention, the temperature adjustment device other thanthe coolant pipe 55 can also be disposed inside the motor compartment 3.However, considering the connection characteristics of the radiator 50and the coolant pipe 55, it is preferably to dispose the temperatureadjustment device in front of the front-wheel driving motor 40.

In the first through third embodiments described above, the fluidconnection port 201 (connected to the fuel gas channel 211) used for thefuel gas is disposed at the innermost position comparing to the fluidconnection ports 202 used for the oxidizing gas and the fluid connectionports 203 used for the coolant. Therefore, the distance between the fuelgas channel 211 (connected to the fluid connection ports 201) andinvading objects can be maximized even in cases where physical objectsenter from the outside in a front end collision of the vehicle or thelike. Accordingly, damage of the supply/discharge manifolds 20 can besecurely prevented.

In other words, as a result of the fluid connection ports 201 beingdisposed in the innermost position of the supply/discharge manifold 20,the possibility of invading objects from the outside entering the fluidconnection ports 201 can be greatly reduced even in cases where invadingobjects from the outside interfere with the supply/discharge manifolds20.

In the first through third embodiments described above, the fuel gaspipe 21 that leads the fuel gas from the fuel gas storage tank 65 to thefuel gas channel 211 (connected to the fuel gas connection ports 221) isconnected, from the inside in the lateral direction of the vehicle, tothe connection ports 221 formed on the inside surfaces of thesupply/discharge manifolds 20. Accordingly, even in cases where physicalobjects enter the vehicle 1 from the outside due to a vehicle sidecollision or the like, the distance between the invading objects and thefuel gas pipes 21 can be kept at a maximum distance. Therefore, damageof the fuel gas pipes 21 can be securely prevented.

In other words, since the fuel gas pipes 21 are generally thinner thanother pipes used for the oxidizing gas and the coolant, connectionbetween the fuel gas pipes 21 and the supply/discharge manifolds 20 canbe accomplished in the narrow spaces between the supply/dischargemanifolds 20 and the upper portion of the driving motor 40. Accordingly,even in cases where invading objects enter the vehicle 1 from theoutside during a vehicle side collision or the like, the possibility ofdamage of the fuel gas pipes 21 can be greatly reduced.

In the first through third embodiments described above, thesupply/discharge manifolds 20 are directly coupled to the housing 300 inwhich the fuel cell 10 is mounted via the gaskets 13. Accordingly, thehousing 300 of the fuel cell 10 and the supply/discharge manifolds 20can effectively form a single rigid body, so that the fuel leakagecaused by shifting or the like of the sealing parts between thesupply/discharge manifolds 20 and the housing 300 of the fuel cell 10during a vehicle collision or the like can be prevented. Since thehousing 300 is directly coupled to the supply/discharge manifolds 20 viathe gaskets 13, the fuel cell fluids discharged from the fuel cellstacks 10A and 10B can flow to the supply/discharge manifolds 20 overthe shortest distance. Therefore, water produced inside the fuel cellstacks 10A and 10B can be quickly discharged into the supply/dischargemanifolds 20 by the force of gravity. Accordingly, defective powergeneration of the fuel cell 10 due to flooding can be prevented.Furthermore, since the size of the supply/discharge manifolds 20 can beminimized, the size and weight of the fuel cell system as a whole can befurther reduced.

In the first through third embodiments described above, thesupply/discharge manifolds 20 or the housing of the fuel cell 10 can befastened to the side frame members 7 of the vehicle body frame, and thesupply/discharge manifolds 20 and the housing 300 of the fuel cell 10can be connected to the side frame members 7 of the vehicle body frameas a single rigid body. Therefore, damage of the fuel cell 10 or thesupply/discharge manifolds 20 due to the entry of the side frame members7 toward the motor compartment 3 can be securely prevented even during avehicle side collision or the like.

In the first through third embodiments, the fuel cell 10 includes onepair of the fuel cell stacks 10A and 10B. However, the number of thefuel cell stacks 10A and 10B is not limited to two, and any number ofthe fuel cell stacks 10A and 10B can be used to form the fuel cell 10 tocarry out the present invention.

GENERAL INTERPRETATION OF TERMS

In understanding the scope of the present invention, the term“comprising” and its derivatives, as used herein, are intended to beopen ended terms that specify the presence of the stated features,elements, components, groups, integers, and/or steps, but do not excludethe presence of other unstated features, elements, components, groups,integers and/or steps. The foregoing also applies to words havingsimilar meanings such as the terms, “including”, “having” and theirderivatives. Also, the terms “part,” “section,” “portion,” “member” or“element” when used in the singular can have the dual meaning of asingle part or a plurality of parts. Also as used herein to describe theabove embodiments, the following directional terms “forward, rearward,above, downward, vertical, horizontal, below and transverse” as well asany other similar directional terms refer to those directions of avehicle equipped with the present invention. Accordingly, these terms,as utilized to describe the present invention should be interpretedrelative to a vehicle equipped with the present invention. The terms ofdegree such as “substantially”, “about” and “approximately” as usedherein mean a reasonable amount of deviation of the modified term suchthat the end result is not significantly changed.

While only selected embodiments have been chosen to illustrate thepresent invention, it will be apparent to those skilled in the art fromthis disclosure that various changes and modifications can be madeherein without departing from the scope of the invention as defined inthe appended claims. For example, the size, shape, location ororientation of the various components can be changed as needed and/ordesired. Components that are shown directly connected or contacting eachother can have intermediate structures disposed between them. Thefunctions of one element can be performed by two, and vice versa. Thestructures and functions of one embodiment can be adopted in anotherembodiment. It is not necessary for all advantages to be present in aparticular embodiment at the same time. Every feature which is uniquefrom the prior art, alone or in combination with other features, alsoshould be considered a separate description of further inventions by theapplicant, including the structural and/or functional concepts embodiedby such feature(s). Thus, the foregoing descriptions of the embodimentsaccording to the present invention are provided for illustration only,and not for the purpose of limiting the invention as defined by theappended claims and their equivalents.

What is claimed is:
 1. A fuel cell electric vehicle comprising: adriving motor disposed between a pair of wheels, the driving motorhaving a center top surface and first and second lateral end topsurfaces with the center top surface being positioned vertically higherthan the first and second lateral end top surfaces; a fuel cell disposedabove the driving motor having a plurality of unit cells stacked in avertical direction of a vehicle, the fuel cell including a plurality ofthrough-manifolds configured and arranged to distribute a fuel gas, anoxidizing gas and a coolant to the unit cells; and first and secondsupply/discharge manifolds disposed adjacent to the first and secondlateral end top surfaces of the driving motor, respectively, with bottomedges of the first and second supply/discharge manifolds being disposedvertically lower than the center top surface of the driving motor, andthe first and second supply/discharge manifolds being fluidly coupled tothe through-manifolds to transport the fuel gas, the oxidizing gas andthe coolant relative to the fuel cell, the first and secondsupply/discharge manifolds including a plurality of fluid connectionports for transporting the fuel gas, the oxidizing gas and the coolantat positions that substantially overlap with positions of thethrough-manifolds formed in the fuel cell in a top plan view of thevehicle.
 2. The fuel cell electric vehicle according to claim 1, whereineach of the first and second supply/discharge manifolds includes aplurality of fluid channels fluidly connected to the fluid connectionports such that one of the fluid channels disposed in an outermostposition of the first and second supply/discharge manifold is used fortransporting the coolant.
 3. The fuel cell electric vehicle according toclaim 1, wherein each of the first and second supply/discharge manifoldsincludes a plurality of fluid channels fluidly connected to the fluidconnection ports such that one of the fluid channels disposed in aninnermost position of the first and second supply/discharge manifold isused for transporting the fuel gas.
 4. The fuel cell electric vehicleaccording to claim 3, wherein one of the first and secondsupply/discharge manifolds is configured and arranged to fluidly coupledto a fuel gas pipe connected to a fuel gas storage device mounted on thevehicle at one of the fluid connection ports disposed on an innersurface of the first and second supply/discharge manifold with respectto the lateral direction of the vehicle.
 5. The fuel cell electricvehicle according to claim 1, wherein the fuel cell is housed inside ahousing that is fixedly coupled to the first and second supply/dischargemanifolds.
 6. The fuel cell electric vehicle according to claim 1,wherein the fuel cell is housed inside a housing that is fixedly coupledto a pair of side frame members of a vehicle frame, respectively.
 7. Thefuel cell electric vehicle according to claim 1, wherein the first andsecond supply/discharge manifolds are fixedly coupled to a pair of sideframe members of a vehicle frame, respectively.
 8. The fuel cellelectric vehicle according to claim 1, wherein each of the first andsecond supply/discharge manifolds is formed as a one-piece, unitarymember.
 9. The fuel cell electric vehicle according to claim 1, whereineach of the first and second supply/discharge manifolds is formed byintegrally coupling two separate members.
 10. The fuel cell electricvehicle according to claim 1, wherein the first and secondsupply/discharge manifolds have an identical shape.